Hydraulic time compensator



E. JV. PATTERSON HYDRAULIC TIME COMPENSATOR apt, 15 1953 2 Sheets-Sheet 1 Filed NOV. 25 1949 HTTOQA/fi" Sept" 15, 1953 E. w. PATTERSON 2,651,945

HYDRAULIC TIME COMPENSATOR Filed Nov. 25, 1949 2 Sheets-Sheet 2 wane w: pain-950% QTTOQA/EV Patented Sept. 15, 1953 UNITED STATES PATENT OFFICE HYDRAULIC TIME COMPENSATOR Edgar W. Patterson, Downey, Calif.

Application November 25, 1949, Serial No. 129,233

10 Claims.

My invention relates to a method and apparatus for measuring and subsequently automatically causing the time interval to become equal for both of the one hundred eighty degree (180") half cycles, or the up and down or forward and backward movements of an oscillating or reciprocating machine such as an air balanced pumping unit for oil or water wells. Such an air balanced pumping unit is disclosed in one of my prior patents, Reissue No. 20,287, March 9, 1937.

An air balancing device such as the one shown in my Reissue Patent No. 20,287, March 9, 1937, is highly useful in pumping apparatus for balancing the well load so as to maintain a substantially constant torque on the prime mover. However, changes in the well load cause variations in the torque on the prime mover during different parts of the cycle of the pumping unit and thus cause variations in the time which it takes for the pumping unit to move through each halfcycle. These changes in the well load cause stresses throughout the pumping mechanism which lead to a shortening of the life of the unit.

Consequently, it is an object of my invention to provide a hydraulic time compensator which reacts to deviations in the time intervals of the half-cycles of such an air balanced pumping unit in such a way that the balancing pressure is adjusted to that pressure which will substantially equalize the well load and hence equalize the time interval of the half-cycles of the pumping unit. 1

It is another object of my invention to provide a device which will automatically maintain a constant torque on the prime mover of an air balanced pumping unit for oil or water wells.

Another object of my invention is to provide a mechanism which minimizes stresses throughout an oil or water well pumping unit by keeping it in perfect balance, hence, greatly increasing the life of the pumping unit.

Another object of my invention is to provide a device for automatically adjusting the pumping unit to any change in the well load.

Another object of my invention is to balanced the well load of a pumping unit so accurately that no dissymmetry of balance can be readily detected.

Another object of my invention is to provide a hydraulic time compensator of the character described which can be adjusted to compensate to any poundage over any period of time, within reasonable values, so that the compensator can be used for any type of pumping and will not 2 compensate for merely instantaneous changes in the well load.

A further object of my invention is to provide a twoway air valve which is particularly adapted to use in conjunction with my hydraulic time compensator.

Other objects and advantages of my invention will be apparent from the following description and. claims, the novelty consisting in the features of construction, combination of parts, the unique relations of the members and the relative proportioning, disposition and operation thereof, all as is more completely outlined herein and as is particularly pointed out in the appended claims.

In the accompanying drawings, forming a part of this present specification,

Figure 1 is a side elevation, partly in section, of my entire invention.

Figure 2 is a top plan view of my invention with the metal cover plate I6 removed from the top of metal box I4.

Figure 3 is a sectional View of my two-way air valve, the valve being in its normal position.

Figure 4 is a sectional view showing the operative relationship between my two-way air valve and my compensator unit, the valve being in its uppermost position.

Figure 5 is an elevational view of the part of my apparatus shown in Figure 4, with the valve in its lowered position.

Figure 6 is a sectional view of my two-way valve along the line 6-6 in Figure 3.

Figure 7 is a sectional view of my pump unit along the lines I-1 in Figure 1.

Figure 8 is a sectional view of my compensator unit along the line 8-8 in Figure 1.

Referring to the drawings, my hydraulic time compensator comprises two principal elements, a pump unit I0 and a compensator unit I2. These two units are positioned within and firmly ai'lixed to a metal box I4 which is covered by a metal cover plate I6, the plate being afiixed to box I4 by means of cover plate screws I8.

Pump unit I0 is of the double acting type of fluid pressure pump and comprises an actuating stem 20 secured to a piston 22 by means of pin 24 and adapted to reciprocate within a cylinder member 26. Reciprocal motion is applied to the actuating stem 20 by means of the walking beam or other member of the air balanced pumping unit which reciprocates during the pumping operation at a suitable pivotal connection 28.

An upper head member 30 and a lower head member 32 provide bushings for the actuating r stem 20 and seal the upper and lower ends of cylinder member 26 respectively so that fluid will not flow out of the ends of cylinder member 26. By having actuating stem 2t. extending through the upper head member 36 and partially into lower head member 32, the displacement of piston 22 is rendered substantially equal for equal upward and downward movements. Lower head member 32 is seated against the bottom of metal box [4 and upper head member 36 is provided with a protrusion 33 which snugly fits into a hole 34 provided in the metal cover plate 66, whereby the pump unit ll] is firmly fixed in its operative position within metal box l4 when the cover plate [6 is screwed into position,

Piston 22 divides the space within cylinder member 28 into two chambers, designated as upper displacement chamber 33 and lower displacement chamber 38. Passages 46 and 42 through the wall of cylinder 26 respectively connect the upper and lower displacement chambers 3 3 and 38 with spring loaded discharge check valves 44 and 46 and intake valves 48 and 56. The two spring loaded discharge check valves 44 and 36 are so adjusted as to discharge fluid under precisely the same pressure, as for example, twenty pounds per square inch.

Line 5252 near the top of metal box 54 designates the operating fluid level in my hydraulic time compensator. During the operation of my invention all parts thereof are below line 5252 and are completely filled. with a fluid, preferably oil.

Tubular members 54 and 56, having small passages longitudinally therethrough, are disposed in the wall of cylinder member 26 in such a position that they will respectively connect the upper and lower displacement chambers 36 and 38 with additional upper and lower displacement chambers 56 and G0, which are disposed within my compensator unit !2.

Compensator unit l2 is constructed similarly to pump unit it, regarding its cylindrical nature, the construction of its ends and the way in which it is a-fflxed within the metal box 14. However, the internal construction of my compensator unit differs materially from my pump unit l0.

Displacement chambers 58 and 50 lie within a cylinder 62, and the displacement chambers 58 and 66 are separated by a free moving piston 64.

Piston 64 is fitted in sealed relationship within cylinder 62, and has a passage 56 through the center thereof which fits snugly around, but in slideable relationship to, a movable actuating stem 68. At the upper and lower ends of cylinder 62 I provide head closure members it and '52,

respectively, which are similar in construction to head members 30 and 32 of pump unit Iii. Actuating stem 68 extends partially into the bore 16 of lower head closure member '52 and penetrates completely through the upper head closure member "it. By this arrangement the volume of fluid required to move the piston $4 within the cylinder 62 a given distance in either direction will be exactly the same.

Stop collars 1S and 81 are affixed to actuating stem $6 on opposite sides of piston 64 respectively by means of pins 62 and 64. Stop collars '52 and 30 are so spaced on the actuating stem 68 that piston 6A. is free to move within the cylinder 52 and around the presently stationary actuating stem 68 a fixed distance without encountering resistance of any nature, other than the friction between piston 64 and the bore of cylinder 62 and the friction between actuating stem 58 and the cylindrical surface of passage 6E through piston 64. However, if piston 64 moves a sumcient distance, either upward or downward, it will encounter one of the stop collars, 73 or 86, depending on which direction the piston is moving, If piston 64 is moving upward it will encounter stop collar 18 and continued upward movement of the piston will cause an upward movement of the entire actuating stem 68. Similarly, a downward movement of piston 64 will cause a downward movement of actuating stem 68. This movement of actuating stem 68 is restricted within relatively close limits by the short spaces between stop collars l8 and 66 and the respective head closure members and 12 when the actuating stem 68 is in its normal position, as illustrated in Figure 1.

The normal position of actuating stem 68, as .illustrated in Figures 1 and 3, is maintained by a proper balance between a pair of springs 86 and 88, situated respectively above and below the actuating stem 66. Upper spring 86 is disposed within a two-way air valve 96, and exerts a downward force upon actuating stem 68 through a valve member 92 which is seated on valve seat 54 against downward movement when in the normal position. Thus, spring 86 only causes a downward force upon actuating stem 68 when the stem is moved upward from the normal position by an upward motion of piston 64. Spring 88 is disposed within the bore of lower head closure member 12 and one end of spring 38 rests against the bottom of metal box l4. Spring 88 has about one-half the strength of spring 86, whereby actuating stem 66 is centered at its normal position as gauged by the seated position of valve member 92, spring 88 not being suflicient to cause compression of spring 86.

It is to be understood that the device as herein described is also operable, and will function properly when only one of the tubular members, either 54 or 56, is employed, while the opposite tubular member could be a larger diameter fluid duct or passage. The metering efl'ect would be the same in either case. Consequently either the singular or the plural term will be used herein with reference thereto.

The normal operation of my hydraulic time compensator is as follows: Actuating stem is reciprocally moved up and down by the reciprocal motion of the walking beam or other moving part of the pumping machine, which is applied through pivotal connection 28. The stroke length of the reciprocal motion of actuating stem 20 is preferably two or three inches. The reciprocating member of the pump is so attached to pivotal connection 28 that the piston 22 is caused to reciprocate within cylinder member 26 substantially in unison with the up and down movement of the pump rod in the well.

So long as the up and down stroke of the pump rod in the well occurs through the same time interval the pump unit It) will alternatively intake fluid through intake valves 48 and and alternately discharge most of said fluid through loaded discharge check valves 46 and 44 under precisely the same pressure. While this continuous pumping operation is taking place a small portion of the fluid under pressure in the upper and lower displacement chambers 36 and 38 will enter the respective tubular members 54 and 56. When piston 22 is moving downward in cylinder member 26 a volume of fluid will pass from lower displacement chamber 38 through tubular member 56 that will be dependent upon the pressure within displacement chamber 38 and the length of time required for the downward stroke. This passage of fluid through tubular member 56 will increase the volume of fluid within displacement chamber 60 of the compensator unit I2 whereby piston 64 freely moves upwardly a slight amount. On the next half cycle when the actuating stem 20 moves in an upward direction, fluid passes through tubular member 54 from chamber 30 of the pump unit I into chamber 58 of the compensator unit I2, thereby causing piston 64 to move slightly in a downward direction. When piston 64 is moving upward in cylinder 62 fluid passes from chamber 58 through tubular member 54 back into chamber 36 under only slight pressure, and similarly when piston 64 is moving downward, fluid is transferred through tubular member 56 from displacement chamber 80 into chamber 38. If the period of time required for the downward movement of actuating stem 20 is exactly the same as the period required for its upward movement, exactly the same amount of fluid will be transferred for each half cycle from chamber 38 to chamber 60 as will be transferred from chamber 38 to 58. Therefore, it is plain to see that in this situation the piston 64 will simply move upward and downward freely without contacting either one of the stop collars I8 or 80. This free reciprocal movement of piston 64 is only slight due to the very small amount of fluid which can pass through the small longitudinal passages through tubular members 54 and 56.

In the event that the time interval required for the up stroke of the pump rod happens to be greater than the time interval for the down a stroke of the pump rod as a result of the pumping machine being underbalanced, a slightly greater amount of fluid will pass from chamber 36 into chamber 58 for each cycle than will pass from chamber 38 to chamber 60. ence in the time period for the upward and the downward strokes of actuating stem '20 is only slight, for example, one one-hundredth of a second, the amount of fluid which passes into chamber 58 during one half cycle may only be about a drop more than the amount of fluid which passes into chamber 60. Thus, as the pumping proceeds the additional amount of fluid transferred to chamber 58 over the amount that is transferred to chamber 60 becomes cumulatively greater and the piston 64 becomes displaced in a downward direction. When piston 64 has moved downward a sufficient distance it will engage stop eollar 80 and cause the actuating stem 68 to move in a downward direction against the upward pressure exerted by spring 88. This downward motion of actuating stem 68 actuates the two-way air valve 90 in the manner hereafter described so as to provide additional air pressure in the air balancing system of the pumping unit. When the pump again becomes properly balanced, or rather slightly overbalanced, the down stroke time interval becomes greater than the up stroke interval and fluid is accumulated within the chamber 60 at the expense of some of the fluid in the chamber 58. This causes the actuating stem 86 to move back up to its normal position, cutting off the additional supply of compressed air to the air balancing system of the pumping unit.

In the event that the down strokes of the pump rod of the pumping unit happen to be slower than the up strokes as a result of the pumping unit being in an overbalanced condition the piston 64 will gradually move in an up- If the differward direction, finally engaging stop collar '18 and moving the actuating stem 08 upward. This upward motion of the actuating stem 68 actuates the two-way air valve 90 in such a manner that the air supply means is cut off and a certain amount of the pressure within the air balancing system of the pumping unit will be released, thereby bringing the system back down to a perfectly balanced condition, whereby the piston 64 will move back down so as to leave the two-way air valve 90 in its normal, unactuated condition.

My two-way air valve 90 is attached to the compensator unit I2 by means of a screw ring 96. When actuating stem 68 is in the normal position, the valve member 92 is in its lowermost position, resting against the valve seat 94. Upper face 98 of actuating stem 68 rests flush against valve stem face I00, preventing the passage of air through valve stem bore I02. Thus, when the actuating stem 68 is in its normal position air cannot pass from the source of air pressure through air duct I04, around the reduced diametral portion I08 of valve member 92 and out the two-way air passage I08 because of the seal provided between the valve member 92 and the valve seat 9 3. Similarly, when the actuating stem 68 is in its normal position, no air can pass through two-way air passage I08, valve stem bore I02 and out the air duct IIO because of the seal provided between the valve stem face I00 and the upper face 98 of actuating stem 68.

When the valve stem 68 is in the uppermost position, as shown in Figure 4, corresponding to an overbalanced condition of the air balanced pumping unit, actuating stem 68 moves the valve member 92 upward against the downward force of compression spring 80, unseating valve member 92 from the valve seat 94. This permits air which is being applied to air duct I04 to pass through the duct I 04, around the reduced diametral portion I06 of valve 92, past the valve seat 94 and out of the two-way air valve 90 through two-way air passage I08. Passage I08 leads to an unloader device (not shown) attached to the air compressor or other source of air supply for replenishing air when required in the balance system of the pumping unit. This air pressure on the unloader device provided through the two-way air passage I08 actuates the unloader device in such a manner that the pressure in the air balancing system remains fixed at this pressure.

On the other hand, when the actuating stem 68 is moved in a downward position from its normal position so that it is situated as shown in Figure 5, air is permitted to pass from twoway air passage I08 into the two-way air valve 90, through the valve stem bore I02, past the valve stem face I08 and out into the atmosphere through duct III). Ihis reduces the pressure against the unloader device as provided through two-way air passage I08, thereby actuating the unloader device in such a manner that air will be pumped from the air compressor or other source of air pressure into the balance system of the pumping unit, thereby causing the balancing system to be slightly overbalanced which in turn causes the actuating stem 83 to move in an upward direction.

Piston 64 does not continually move from its extreme upper'position to its extreme lower position, and back again. There is a small set pop valve H2 in the two-way air passage I08 from the two-way air valve 50 to the unloader device of the air balancing system of the pumpton 64 to move into its upward position from its lowermost position, at which time the set pop valve reduces the pressure in the balancing system to the properly balanced state, whereby piston 64 will remain in its free-moving position.

My two-way air valve 33 is my preferred device to use in conjunction with my compensator unit l2 to actuate the unloader device for controlling the amount of air pressure in the air balancing system. However, it is to be understood that other devices can be used in place of my twoway air valve for enabling the unloader device to be actuated by movements of the actuating stem 68 of my compensator unit 12. For example, in certain applications of my invention wherein it may be advantageous to use elec- .i

tricity instead of air as the secondary actuating medium, it would be a simple matter for anyone skilled in the art to substitute an electric make and break contact device for the two-way air valve whereby a clutch could be caused to engage :7.

and disengage, in turn causing an air compressor to supply and discharge air respectively precisely in the same way that my two-way air valve supplies and discharges air.

Although my hydraulic time compensator is particularly adapted to use in conjunction with air balanced oil and water pumping systems, it is to be understood that it may be used in conjunction with any machine employing the use of reciprocal motion.

My invention comprises a minimum number of moving parts and is sturdy and relatively simple and inexpensive to manufacture. The accuracy of my invention has been confirmedby operations in the field.

It is to be understood that the form of my invention herein shown and described is my preferred embodiment and that various changes in the shape, size and arrangement of parts may be resorted to without departing from the spirit of my invention, or the scope of the appended claims.

I claim:

1. A hydraulic time compensator for air balanced reciprocating machines including a time compensator unit having an output member, a double acting type of fluid pressure pump which is actuated by synchronous reciprocal motion from said machine, a fluid coupling between said pump and said time compensator unit and a two-way air valve utilizing said output member as its input member.

2. A hydraulic time compensator for reciprocating machines including a time compensator unit, a pair of fluid chambers within said time compensator unit, actuating means disposed in said time compensator unit and adapted to move respectively in two different longitudinal directions responsive to a given quantity of fluid respectively in each of said fluid chambers and means for introducing a quantity of fluid respectively into each of said fluid chambers which is directly proportional to the time periods of the respective half cycles of the reciprocal motion of said machine.

3. A hydraulic time compensator for reciprocating machines including a time compensator unit having a cylinder and a piston which is longitudinally freely movable a fixed distance about a central position within said cylinder, actuating means disposed in said time compensator unit and adapted to move respectively in two different longitudinal directions responsive to motion of said piston when the latter is farthest from said central position and means for introducing a fixed quantity of fluid into the respective chambers on either side of said piston which is directly proportional to the time periods of the respective half cycles of the reciprocal motion of said machine, said actuating means being operatively connected to means for balancing said machine.

4. A hydraulic time compensator for reciprocating machines including a time compensator unit having a cylinder and a piston which is longitudinally freely movable about a central position within said cylinder, a pair of members adapted to be alternatively contacted by said piston when the latter is furthest from said central position, means for introducing a fixed quantity of fluid into the respective chambers on either side of said piston which is directly proportional to the time periods of the respective half cycles of the reciprocal motion of said machine and actuating means operatively connecting each of said pair of members to means for balancing said machine.

5. A hydraulic time compensator for reciprocating machines including a time compensator unit having a cylinder and a piston which is freely movable about a central position within said cylinder, actuating means disposed in said time compensator unit and adapted to move respectively in two different directions responsive to motion of said piston when the latter is farthest from said central position, a double acting type of fluid pressure pump which is actuated by reciprocal motion from said machine and a fluid coupling between the two respective pumping chambers of said pump and the respective chamers on either side of said piston, said actuating means being operatively connected to a means for balancing said machine.

6. A hydraulic time compensator for reciprocating machines including a time compensator unit having a cylinder and a piston which is freely movable about a central position within said cylinder, a pair of members adapted to be alternatively moved by said piston when the latter is furthest from said central position, a double acting type of fluid pressure pump which is actuated by reciprocal motion from said machine, a fluid coupling between the two respective pumping chambers of said pump and the respective chambers on either side of said piston and actuating means operatively connecting each of said pair of members to means for balancing said machine.

7. A hydraulic time compensator for reciprocating machines including a time compensator unit, a pair of fluid chambers within said time compensator unit, actuating means disposed in said time compensator unit and adapted to move respectively in two different directions responsive to a given quantity of fluid respectively in each of said fluid chambers, means for introducing a quantity of fluid respectively into each of said fluid chambers which is directly proportional to the time periods of the respective half cycles of the reciprocal motion of said machine and a two-way air valve connected to said actuating means and adapted to operatively inter-connect said actuating means and means for balancing said machine.

8. A hydraulic time compensator for reciprocating machines including a time compensator unit having a cylinder and a piston which is freely movable about a central position within said cylinder, actuating means disposed in said time compensator unit and adapted to move respectively in two different directions responsive to motion of said piston when the latter is farthest from said central position, means for introducing a quantity of fluid into the respective chambers on either side of said piston which is directly proportional to the time periods of the respective half cycles of the reciprocal motion of said machine and a two-way air valve connected to said actuating means and adapted to operatively interconnect said actuating means and means for balancing said machine.

9. A hydraulic time compensator for reciproeating machines including a time compensator unit, a pair of fluid chambers within said time compensator unit, actuating means disposed in said time compensator unit and adapted to move respectively in two different longitudinal directions responsive to a given quantity of fluid respectively in each of said fluid chambers, a double acting type of fluid pressure pump which is actuated by a reciprocal motion from said machine, a fluid coupling between the two respective pumping chambers of said pump and the respective chambers within said compensator unit and a 10 two-way air valve connected to said actuating means and adapted to operatively inter-connect said actuating means and means for balancing said machine.

10. A hydraulic time compensator for reciproeating machines including a time compensator unit having a cylinder and a piston which is freely movable about a central position within said cylinder, actuating means disposed in said time compensator unit and adapted to move respectively in two different directions responsive to motion of said piston when the latter is farthest from said central position, a double acting type of fluid pressure pump which is actuated by reciprocal motion from said machine, a fluid coupling between the two respective pumping chambers of said pump and the respective chambers on either side of said piston and a two-Way air valve connected to said actuating means and adapted to operatively inter-connect said actuating means and means for balancing said machine.

EDGAR W. PATTERSON.

References Cited in the file of this patent UNITED STATES PATENTS (Corresponding U, S. 2,165,001, July 4, 1939.) 

